1. Field of the Invention
This invention relates to gas turbine engines and, more particularly, to a turbine rotor cooling seal.
2. Description of the Prior Art
The need for cooling turbine rotor parts is well known in the gas turbine engine art. This need is particularly pronounced during periods when the engine is being operated at or near full power and thus, the temperature of the mainstream gas is at its highest point. The direct impingement of such high temperature gas upon critical rotor components, for example the rim of the rotor disk, causes severe overheating of the critical components, thereby decreasing their useful life.
One prior art approach to this problem has been to construct the critical rotor components utilizing materials which are not as susceptible to deterioration from being exposed to excessive heating. This approach is not entirely satisfactory, however, since such materials are costly and result in the addition of unnecessary weight to the rotor, thereby decreasing overall engine performance and operating efficiency.
An alternate prior art approach has been to provide a continuous flow of cooling compressor discharge air for mixing with and lowering the temperature of the hot mainstream gas prior to its impingement upon the critical rotor components. This approach is also unsatisfactory because the diversion of large amounts of compressor discharge air for cooling purposes significantly lowers the output power of the engine and decreases engine operating efficiency.
The present invention is directed to a simple and effective solution to the problem of protecting critical rotor components from the detrimental effects of direct mainstream gas while maintaining or increasing engine output power and operating efficiency.